1. Field of the Invention
This invention relates to an antenna for a cellular telephone and more particularly to a variable extended cable antenna which has two electrical functions; namely, first as a fully extended directly coupled helical top loaded 3/4 wave antenna and second as a 1/4 wave helical antenna when the antenna is retracted into the telephone.
2. Description of the Prior Art
Cellular telephones have become extremely popular in recent years. It has been found that the cellular telephones are more compact and portable when they are provided with retractable antennas. However, the retractable characteristics of the antenna interferes with the performance thereto especially when the antenna is retracted.
One type of retractable antenna is that manufactured by Galtronics which has been marketed as a "Retractable" two-in-one antenna. The Galtronics antenna consists of a full 1/4 wave element plus a 1/4 wave helical element in one antenna. There is no electrical connection between the two elements which therefore limits the antenna to a 1/4 wave antenna.